Kirby said Saturday he was "extremely confident" that if the House voted on expulsion he would have prevailed.
However, he said he did not want to continue to put his family, himself and his friends "through more of this situation."
Kirby was divorced several years ago.
"I cannot, in good conscience, continue to fight against unfounded accusations and what I believe to be unreasonable committee recommendations when the end result will ultimately be that the people of House District 75 will not have a voice at the state Capitol for the next two years," Kirby said. "The committee has ensured that this would have been a lose-lose situation for me and my district."
"Being a representative of the people has been the highest honor of my life," Kirby said. "I am and will always be proud of the legislation I have carried to protect children, strengthen athletic regulations, make youth sports safer, and many other positive reforms I have carried."
As a constituent of HD70, we citizens went unrepresented for an entire year because of a scandalized representative couldn't keep it in his pants, followed by an election board who couldn't conduct a secure special election. It was greatly disheartening.